Longitudinal joint for concrete roadways



March 5, 1929. R. o. GREGG ET AL l,7 04,431

' LOIIGI'I'UDINAL JOIN! FOR CONCRETE ROADIAYS flied lay 27, 1921 fioesnrfl. GREGG, AND fiPAM-r L. (SH/DA. 547,

Patented Mar. 5, 1929.

UNITED STATES PATENT OFFICE.

ROBERT D. GREGG AND FRANK L. srnnmm, or KANKAKEE, ILLINOIS.

LONGITUDINAL JOINT FOR CONCRETE ROADWAYS.

Application filed May 27, 1927. Serial No. 194,583.

This invention relates to that class of concrete roadways, in which the roadway formed in sections of slabs of an approved size and separated by transverse expansion joints. in connection with a central longitudinal joint providing a flexible or hinge connection at the crown or center of. the roadway, examples of which are set forth in our prior Letters Patent No. l,b'0el,99(l, and 1., 604,991, dated Nov. 25, 1926, and the present improvement has for its objects To provide a structural formation and association of parts in the above mentioned type of longitudinal joints of concrete roadways whereby an interlocking connection is provided at central or other longitudinal joint of the roadway and preferably of a limited hinge or flexible nature, with such interlocking connection of parts of suflicient strength to tie the roadway see tions or slabs together against any tendency to move apart or separate, as well as to re sist shearing action caused by heavy trailic;

To provide a simple and etlieient means whereby the above mentioned interlocking connection of the roadway sections or slabs attained by a series of cup shaped shells, preferably of an oblate spheriodal form, fixed in place in an edge of the roadway section or slab and adapted to be filled with the concrete mass of an adjoining roadway section or slab to form the interlocking means between the sections, durin the serial operation of forming the roadway sections or slabs, all as will hereinafter more fully appear.

In the accompanying drawing:

Fig. 1, is a detail transverse section show ing the preferred form of the present invention as applied to the longitudinal center joint of a sectional concrete roadway.

Fig. 2, is a similar view illustrating the means where the cup shaped shells of the present interlocking connection are placed in the edge of a roadway slab or section.

Fig. 3, is a detail transverse section, similar to Fig. 1 showing a parting strip that supports the series of interlocking joint forming cups or shells, is left as an imbedded portion of the roadway.

Fig. 4, is a detail elevation of an end portion of the parting strip shown in Fig. 1.

Fig. 5, is a detail section illustrating a modified means of attachmentof the hold ing means of the cup shaped shells of the invention.

Like reference numerals indicate like parts 111. the several views.

j The present improvements are more es peciaily adapted for use in the formation of concrete roadways of the sectional or slab type. and comprises means, and the use and application, to form an interlocking connection, preferably of the flexible or hinge type, between the longitudinal edges of the roadway sections or slabs. Such application involving the formation and normal setting or hardening in place of one concrete roadway section or slab, before an adjoining and succeeding section or slab is formed in abutting relation to the first mentioned section or slab. j

In the practical application of the invention and in the preferred manner indicated in Figs. 1 and 2, a form or mold board 1 of either wood or metal,- isproperly anchored in place to constitute a wall of the cavity in which the concrete roadway slabor section 2 molded. Suchboard carries at or near its mid-height a series of .cup shaped shells 30 3, preferablyo'lf the oblate spheriodal form shown, and in which theinouth or opening of each shell is of a less diameter than that of the interior of the shell. The shells 2 are secured in spaced relation along the length of the moldboard 1, usually twelve inches apart, and the preferred constructions are detachably connected to said mold. board, so that the same may be subsequently removed leaving-the series of shells 3 fixeiil 9c able manner by a prolate shapedshell l secured by bolts 5 to the mold board 1, with the open mouthed end of an aforesaid oblate spheriodal cup shaped shell 3 adapted to be snapped over a holding shell 4 to provide the required detachable engagement between.

the parts.

It is within the scope or province of this part of the invention to secure the shells 3 in place on the board 1 by other ordinary detachable connecting means, such for instance as by means of a headed nail 6 passing through the'crown or central portion of the shell and driven into the mold board 1 as shown in Fig. 5, with the head of said nail shel in the subsequent removal of the mold board and leaving the shell 3 in the conadapted to be torn out of the wall of the crete section or slab 2. Usually the margin of the opening in the shell 3 for the nail 6 will be weakened in any usual manner to permit ready tearing apart of the shell wall and nail head above referred to.

lVith the above described construction, no parting strip employed and the concrete mass of one roadway section or slab 1, is in direct contact with an adjacent section or slab.

When however a parting strip is desired at such point, the same is provided by a plate or strip 7 adapted to remain in place after the inoiding of adjacent rot ay slabs orsections, with said parting strip '1' consisting of a plate or strip of metal or like material formed with as ries oi orilices 8 along its length and near its mid-height, with the margin of each of the openings 8 formed with a cluster oi retaining prongs 9 and boss 10, adapted to engage in out turned marginal riin 11 at the mouth or opening ot a cup shaped shell. 3, as illustrated in Figs. 3 and t. With such constriction the concrete material of the roadway section or slab last formed is adapted to enter through the openings or orifices 8 of the parting strip 7 and the aligned mouth or orifices oi? the cup shaped shells 3, to fill the interior of said shells and constitute the interlocking connections of the present invention.

In the practical carrying on of the invention, and with the form or mold board 1 in place and carrying the series of cup shaped shells 3, the concrete section or slab is poured or molded in the forming cavity and around said shells as illustrated in Fig. 2. At the end of about twenty four hours for the hardening of the poured mass of concrete, the form 'or mold board 1 can be saiiely stripped oil, leaving the series 0t cup shaped shells 3 securely imbedded in the concrete mass of the section or slab just formed. In that it has been from a number oi. actual tests that the joint formed by a cup shaped shell 3, two and one-half inches in diameter will withstand a pulling stress of three hundred pounds at the end of twenty four hours after having been set in a concrete mass, there is little if any liability to pulling out when the form board 1, is talzen away. It has also been found that the shearing strength of the ball like portion of the present interlocking construction is more than five thousand pounds for a 1.2-l, mixture, and consequently the roadway sections or slabs will be maintained at a uniiorm elevation under heavy tral'lic or trust actions.

Before the neat adjacent roadway section or slab is molded, the one previously inoided should have its vertital edge coated with a heavy oil or like repellant substance, with a view to render the joint or seam both waterprocf and flexible. And with a view to aid in such flexibility in the joint the interior surface oi. the cup shaped shells 5, should be sprayed or coated with such heavy oil or like l'GPGllfilll? substance, in order to avoid adhesion.

By placing the cup shaped shells 3 in the longitudinal marginal edges oi a concrete roadway, provision is made for the subsequent :tormzdion of added late 'al sections or slabs, and. their eilcctive attachment to the road 'ay already formed, when an increase in traiiic required a widening of the road way.

Having thus fully described our invention what we claim and, desire to secure by Letters Patent, is:

A longitudinal joint for sectional concrete roadways, comprising a series of cup shaped shells molded in a vertical edge oil? a roadway section, the entry mouth of each shell being of a less diameter than its interior, the interior oi? said shells adapted to be filled through the entry months with the concrete material oi a subsequently l ornied adjoining roadway section to provide an interlocking joint between said sections.

In testimony whereof we aiiix our signatures.

ROBERT D. GREGG. F EANK L. SHIDLER. 

